Electronic apparatuses such as cellular phones and smart phones are equipped with a miniaturized camera. The miniaturized camera of this type is an automatic focusing type. The miniaturized camera of this automatic focusing type includes a lens driving device for actuating the lens to move.
Japanese Registered Utility Model No. 3186519,U discloses a lens driving device that includes: a tubular lens holder being capable of holding a lens member which is disposed above an imaging sensor; a biasing member supporting the lens holder so that the lens holder can move along the optical axis direction; a fixing member for fixing one part of the biasing member; and a driving mechanism having magnets, a coil, and a yoke and which driving mechanism moves the lens holder along the optical axis; wherein the biasing member includes an upper sheet spring fixed to the top of the lens holder and a lower sheet spring disposed opposing to the upper sheet spring and fixed at the bottom of the lens holder; the fixing member is provided with a first abutment reception to which a first abutment part being provided at the upper part of the lens holder can abut and a second abutment reception to which a second abutment part being provided at the bottom part of the lens holder can abut; and wherein in an initial state in which the lens holder is oriented into the horizontal direction whose optical axis is orthogonal to the vertical direction and in which no electric current flows through the coil, the distance between the first abutment part and the first abutment reception is set to be larger than the distance between the second abutment part and the second abutment reception.
Japanese Patent Application Laid-Open Publication No. JP2009-282090,A discloses a lens driving device including: a tubular lens body including a lens; a driving coil fixedly disposed around the lens body; permanent magnets disposed opposing to the driving coil; an outer yoke to which the permanent magnets are disposed at its inner wall; and an upper elastic member and a lower elastic member disposed at upper and lower sides of the lens body and supporting the lens body so that the lens body can move along the optical axis without moving in the radial direction of the lens body; wherein each of the upper elastic member and the lower elastic member has an inner circumference side end which is attached to the lens body and an outer circumference side end which is attached to the outer yoke; the position of the lens body is adjustable along the optical axis direction by an interaction of a magnetic field of the permanent magnets with a magnetic field of an electric current flowing through the coil when the electric current flows through the coil; and wherein when no electric current flows through the coil, the lens body is positioned in a focus adjustable region of the lens body along the optical axis direction except an infinity focus position and a macro focus position.